Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P56851 (epididymal)
 11,273 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The major glycoprotein on the plasma membrane of testicular spermatozoa labelled with the galactose oxidase/NaB3H4 technique has mol.wt. 110 000. As spermatozoa pass through the epididymis, labelling of this glycoprotein disappears and is replaced by labelling of a 32 000-mol.wt. protein. The latter protein is a major component of epididymal secretions. The evidence suggests that it is inserted into or absorbed on to the plasma membrane, and since its appearance on spermatozoa correlates with the acquisition of fertilizing capacity it should serve as a good marker for assessing maturation in vitro.
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PMID:Labelling of membrane glycoproteins on rat spermatozoa collected from different regions of the epididymis. 734 Aug 48

Spermatogenesis is a process in the testis that involves meiotic cell division and spermiogenesis. The mechanisms of regulation and its associated proteins are mostly unknown. This publication shows the two-dimensional (2-D) gel electrophoresis protein map obtained from rat testis using nonlinear 3.5-10 immobilized pH gradients for the first-dimensional separation. Eighteen proteins were successfully identified in the SWISS-PROT protein database using amino acid analysis of proteins recovered from polyvinylidene difluoride (PVDF) membranes and verified for one of them by comparison with Anderson's rat liver reference map. Fourteen new polypeptides were identified and four were previously known. Two of these new proteins were closely related to the spermatogenetic process. T-complex protein 1 is expressed in large amounts in germ cells. Androgen-dependent sperm-coating glycoprotein is secreted by epididymal cells. In order to detect changes in protein expression during meiosis and spermiogenesis, spermatocytes and round spermatid cell populations were purified by centrifugal elutriation and compared. In this way several proteins not found in the spermatocyte 2-D images could be high-lighted. The sperm-coating glycoprotein was thus shown to be present in large amounts in round spermatids.
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PMID:Spermatocytes and round spermatids of rat testis: protein patterns. 749 70

Hyaluronic acid, a major component of the extracellular matrix, plays an important role in the regulation of different cellular processes, e.g., locomotion, cell-cell interaction during morphogenesis, and differentiation. Distribution of hyaluronic acid with respect to the role of sperm hyaluronidase in sperm penetration and gamete interaction is well established. In order to elucidate this mechanism, in our current study we have identified and demonstrated, for the first time, the presence of a 68-kDa cell surface hyaluronic acid binding glycoprotein (HABP) in spermatozoa of different species (rat, mice, bull, and human) by immunoblot analysis and indirect immunofluorescence using the polyclonal antibodies raised against purified HABP. Furthermore, we were able to demonstrate a differential distribution of 68-kDa HA binding protein on the sperm head, midpiece, and tail of different species. To identify its role in sperm function, we observed its declining pattern during epididymal maturation and also the inhibition of sperm-oolemmal adherence by pretreatment of the sperms with anti-HABP antibodies. We have further observed its in vivo phosphorylation in motile spermatozoa. All our data clearly indicate that sperm hyaluronan binding protein may have a specific role in sperm maturation, motility, and fertilization processes.
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PMID:Evidence for presence of hyaluronan binding protein on spermatozoa and its possible involvement in sperm function. 751 32

The localization of the neural cell adhesion molecule L1 in the male urogenital tract (including seminal vesicles and prostate) of the mouse and bull was investigated using immunocytochemical and immunochemical methods in order to better understand the function of this glycoprotein in non-neural tissues. L1 antibodies labeled non-myelinated nerves in all portions of the urogenital tract investigated. However, L1 immunoreactivity was also found between epithelial cells of several regions of the urogenital system including epididymal tail, deferent duct, ejaculatory duct and seminal vesicles. Some L1 immunoreactivity was also demonstrated between epithelial cells of murine urinary bladder and urethra. The specificity of the immunoreaction was verified by western blots. There was no correlation between L1 expression and proliferating activity as revealed by double immunocytochemistry using various markers of cell proliferation. This unexpected expression of L1 in nonneural tissues is mainly restricted to non-proliferating epithelia of those portions of the urogenital tract that are derived from the Wolffian duct. It is suggested that L1 in these epithelia could enhance the mechanical resistance and reduce transepithelial permeability.
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PMID:Immunolocalization of the neural cell adhesion molecule L1 in non-proliferating epithelial cells of the male urogenital tract. 764 7

The binding of the spermatozoon to the zona pellucida is a species-specific phenomenon. We have previously shown that the binding of hamster sperm to the homologous zona pellucida involves a sperm 26-kDa glycoprotein, the P26h, originating in the epididymis. In order to establish to what extent this sperm protein is involved in the species-specific recognition of the egg's extracellular coat, we have compared the inhibitory properties of anti-P26h antibodies in a sperm-zona pellucida assay using hamster and mouse gametes. Anti-P26h IgGs inhibit, in a dose-dependent manner, gamete interactions in both species, although in a less efficient manner in the mouse than in the hamster. While anti-26kDa Fab fragments are as efficient as the intact IgG to inhibit hamster sperm-zona pellucida binding, they have no effect on mouse gamete interaction. ELISA, Western blot, and immunohistochemical experiments have been performed in order to characterize the mouse antigen(s) recognized by the anti-P26h antiserum. ELISA and Western blots showed that this antiserum recognized two proteins on mouse spermatozoa that are less reactive than the hamster P26h. These antigens are localized in the acrosomal region of epididymal spermatozoa of both species. These results indicate that the hamster P26H involved in zona pellucida interaction has certain unique epitopes, while others are common to the sperm of both species.
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PMID:Comparative immunoreactivity of mouse and hamster sperm proteins recognized by an anti-P26h hamster sperm protein. 765 78

It is well established that the epididymis is the site where spermatozoa are matured and stored, but our understanding of the regulation of epididymal epithelium functions and their effects on spermatozoa is still fairly limited. The most active regulator of epididymal functions seems to be dihydrotestosterone, the 5 alpha-reduced metabolite of testosterone. Our laboratory has focused on the regulation of 5 alpha-reductase, with studies encompassing its messenger RNA, protein and enzyme activity. We have also investigated the hormonal regulation and distribution of other specific key proteins found in epididymal epithelial cells that play critical roles in the function of these cells. These proteins include clusterin or sulfated glycoprotein-2 and the glutathione S-transferases (GST). Using complementary experimental approaches, including orchidectomy and hormonal replacement, efferent duct ligation, and developmental studies, we have established that 5 alpha-reductase enzyme activity is present in both nuclear and microsomal fractions; the nuclear enzyme appears almost exclusively in the initial segment of the epididymis. In addition, 5 alpha-reductase activity and the mRNAs for both the type 1 and type 2 form of the enzyme are regulated differentially with respect to age and site within the epididymis. Immunolocalization of the protein has revealed that it is located in principal cells and that its subcellular location is dependent on the region of the epididymis. These results indicate that there is both transcriptional and post-transcriptional regulation of the expression of 5 alpha-reductase. Clusterin is a hydrophobic protein secreted by Sertoli cells and found in high concentration in the epididymis. This glycoprotein is expressed at its highest levels in the initial segment and caput epididymidis and at very low levels in the corpus and cauda epididymidis of the intact rat, and it exhibits a novel pattern of androgen regulation. In the areas of highest expression, there is no androgen dependence; however, orchidectomy causes a dramatic increase in the message for clusterin, which is suppressible by androgens in the segments where expression is normally lowest. The GSTs are a family of enzymes thought to play a key role in detoxification. Members of the GST family are expressed in a region-dependent manner along the rat epididymis. We have found that the localization of one member of this enzyme family, GST P, or subunit Yp, is selective for basal cells in the corpus and cauda epididymidis.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Regulation of epididymal epithelial cell functions. 771 Nov 92

Plasma membrane proteins were extracted either from epididymal sperm after incubation with ampullary gland secretion or from uterine sperm derived from surgically treated males belonging to the following groups: TX, excision of all accessory sex glands (ASG); AGX, bilateral excision of ampullary glands; AG, excision of all ASG except ampullary glands; and SH, sham-operated. Total membrane protein, glycoprotein, and SDS-PAGE of individual polypeptide subunits were quantified. After incubation with ampullary gland secretion, both protein and glycoprotein concentrations of epididymal sperm membrane were increased. The protein profile was also significantly altered, with the removal of the 43- and 71-kD subunits and the addition of the 36- and 50-kD subunits. The in vitro results confirmed this proteolytic effect of ampullary gland and other ASG on the 43- and 71-kD subunits, despite a reduction in membrane protein concentration. Modification of the 17-, 20-, 25-, 28-, 56-, and 66-kD proteins were also observed. This report is the first demonstration that the ampullary gland is capable of modifying proteins on the sperm surface.
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PMID:Quantitative electrophoretic study of the modification of sperm plasma membrane by the ampullary gland in the golden hamster. 778 88

Previous studies from this laboratory have identified rat epididymal luminal fluid acid beta-D-galactosidase activity which also optimally hydrolyses a glycoprotein substrate at neutral pH [Skudlarek, Tulsiani and Orgebin-Crist (1992) Biochem. J. 286, 907-914]. We have now separated the luminal fluid beta-D-galactosidase into two molecular forms by ion-exchange chromatography on a column of DE-52. The separated enzyme activities were purified to an apparent homogeneity by molecular-sieve chromatography followed by affinity chromatography on a column of immobilized p-nitrophenyl beta-D-thiogalactopyranoside. The purified forms, when resolved by SDS/PAGE under reducing conditions, showed apparent molecular masses of 84 and 97 kDa. Kinetic studies, including a pH-dependent substrate preference and pH-dependent association/dissociation, disclosed no differences between these two forms. The two forms had identical N-terminal amino acid sequences. However, the 97 kDa form contained much more total carbohydrate and sialic acid than the 84 kDa form. The carbohydrate moieties in the two forms were assessed by comparing their size on SDS/PAGE before and after treatment with endo-enzymes. The removal of N-linked glycans by treatment with N-glycanase or endoglycosidase F generated de-N-glycosylated polypeptides of an apparent molecular mass of 70 kDa, and indicated that the two forms contained varying amounts of asparagine (N)-linked high mannose/hybrid-type and biantennary complex-type oligosaccharides. This result and the fact that the two molecular forms had identical N-terminal amino acid sequences indicated that the two forms probably have identical or very similar polypeptides. The potential role of the enzyme in modification of sperm plasma membrane (PM) glycoproteins was examined by resolving caput sperm PM proteins (before and after treatment in vitro of the membranes with the purified beta-D-galactosidase) on SDS/PAGE, followed by staining with peanut agglutinin (PNA), a lectin which preferentially binds to Gal beta 1,3GalNAc-linkages found in O-linked glycoproteins. The evidence presented in this report has indicated that a PNA-positive glycoprotein of an apparent molecular mass of 135-150 kDa present on the caput (but not cauda) sperm PM is degalactosylated by the digestion in vitro of the membranes with purified luminal fluid beta-D-galactosidase. This result suggests a possible role for the epididymal luminal fluid beta-D-galactosidases.
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PMID:Purification and characterization of two forms of beta-D-galactosidase from rat epididymal luminal fluid: evidence for their role in the modification of sperm plasma membrane glycoprotein(s). 782 52

We have identified a 26-kDa (P26h) epididymal hamster sperm glycoprotein with a species-specific affinity for zona pellucida glycoprotein. Two immunological procedures have been used to document the biological function of this sperm component; active immunization of males against P26h and inhibition of sperm-zona pellucida binding in vitro by anti-P26h antibodies. The immunized male hamsters produced circulating antibodies specific to P26h. Indirect immunofluorescence studies showed that these antibodies bind to the surface of the sperm covering the acrosome. These males were mated with superovulated females, and although spermatozoa were recovered from the genital tract, none of the 194 oocytes recovered were fertilized. In contrast, control males immunized with hamster albumin fertilized 97.4% of the oocytes. Unlike control spermatozoa, those recovered from the cauda epididymidis of males immunized with P26h were characterized by the presence of antibodies at the surface of the acrosome. To establish whether the inhibition of in vivo fertilization by active immunization was occurring at the level of sperm-zona pellucida interaction, a polyclonal antiserum against P26h was raised, and the IgG fraction was added to an in vitro sperm-zona pellucida assay. Compared to the preimmune serum, the IgG inhibited the binding of spermatozoa in a dose-dependent manner. The Fab fragments generated from these IgGs were almost as efficient in inhibiting the binding. These results are discussed with regard to a possible function of P26h in hamster gamete interaction.
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PMID:Inhibition of in vivo fertilization by active immunization of male hamsters against a 26-kDa sperm glycoprotein. 788 3

A three-dimensional profile method of detecting amino-acid sequences compatible with the tertiary structure of any protein has been applied to the lipocalin family of 8-stranded beta-barrels. Profiles derived from six well-resolved lipocalin crystal structures were used to search a comprehensive, non-redundant protein sequence database. Each profile identified a sub-group of lipocalin sequences although no single profile was sufficient to identify the whole family. The alpha-1-acid glycoprotein sub-family was not identified by any lipocalin profile, indicating that known sequence differences in otherwise well conserved regions of these proteins may be reflected in structural differences. The predicted similarity between the beta-lactoglobulin and alpha-2u-globulin structures was much more marked than the similarity between their sequences, and alpha-1-microglobulin sequences were found to be compatible with the structure of epididymal retinoic acid binding protein which has an additional long C-terminal helix. Proteins of unknown structure which were predicted to be compatible with the lipocalin fold include a human mucin. In cases where a large protein family of low overall sequence similarity contains a small number of known structures, this technique can be useful in determining or confirming subtle structural relationships between family members.
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PMID:Structural analysis and classification of lipocalins and related proteins using a profile-search method. 794 55


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